How to chain or combine scopes with subqueries or find_by_sql(如何使用子查询或 find_by_sql 链接或组合范围)
问题描述
I would like to perform a query like
SELECT * FROM ( SELECT * FROM products ORDER BY price ASC ) AS s GROUP BY item;
which return the cheapest of all products for each item. Using this subquery is good because it can run in O(N logN) time.
So I can find this with find_by_sql, but it would be nice to be able to chain it with other scopes for Product.
Anyone know how to either write this as a scope or chain scoped and find_by_sql?
You should be able to do something like
Product.from("(SELECT * FROM products ORDER BY price ASC) AS products").group(:item)
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本文标题为:如何使用子查询或 find_by_sql 链接或组合范围
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